Water available from various sources is often contaminated with suspended solids, microorganisms and toxic chemicals. Consumption of water contaminated with microbial contaminants such as bacteria, viruses and cysts is one of the major causes of various water-borne diseases such as cholera, typhoid and diarrhea. Similarly, consumption of water contaminated with toxic chemicals such as arsenic causes various health hazards such as hyperkeratosis of the hands and palms, black-foot disease and skin, lung, liver, bladder and kidney cancer. Significantly, arsenic has been identified as one of the major water contaminants across the world by countries such as Bangladesh, India, United States of America, South America, China, Taiwan and Thailand. It is estimated that worldwide about 137 million people are exposed to arsenic and subsequently its toxicity. West Bengal, Jharkhand, Bihar and Uttar Pradesh are the Indian states having a very high exposure to arsenic induced toxicity and associated health concerns.
This problem is more aggravated in developing countries where most of the population lives in rural areas and is deprived of purified and safe drinking water. In order to avoid such health hazards caused due to microbial and arsenic contamination, water used for drinking and cooking purposes should be made free from these contaminants.
Different interventions have been adopted in the state of the art, which include centralized water treatment plants, community water treatment units and point-of-use (POU) treatment units. However, these state of the art methods are associated with various disadvantages which are described herein below:                a) Centralized water treatment plants require large capital and involve large operating costs. Hence, these methods are available only in urban areas and are not feasible for deployment in remote rural areas.        b) Community treatment units are also not feasible for long term deployment, since these units demand high maintenance and skilled manpower.        c) The point of use (POU) purifiers based on chemical disinfection, ultraviolet radiation treatment and membrane filtration are able to inactivate or remove microbial contaminants but are not effective in reducing arsenic contamination in water.        d) These POU purifiers are priced by targeting relatively affluent urban buyers and are not affordable to most low-income and rural households.        e) The POU purifiers that are based on reverse osmosis technology are expensive and require continuous supply of piped water and electricity for their operation, and are thus, beyond the reach of rural population.        f) The state of the art methods involve the use of continuous supply of water.        g) The state of the art methods involve the use of electricity.        h) The state of the art methods require skilled manpower.        
It is evident that the state of the art processes are inappropriate for widespread use in a majority of developing countries since these processes are expensive and require continuous supply of water. Further, these processes are not able to simultaneously reduce arsenic and microbial contamination in water. Still further, these processes require electricity and skilled manpower for their proper functioning.